>Apr 14, 2021 2:00:05 PM Ralf Quint <freedos...@gmail.com>: >And I stand by my comments that none of Windows 9x/ME is "running on DOS". I >don't have the time right now to provide the detailed proof for that, but just >look at the addresses of some of the DOS services before the booting of the >Windows 9x GUI and afterwards (in a DOS prompt). They will be decisively >different. You can install a TSR before the booting of Windows 9x GUI that >redirects some of the DOS vectors to produce some debug output and you will >not see that debug output when calling the same DOS vector while running under >Windows 9x. That was also the problem with some DOS drivers for some SCSI >adapters for example, which would not work under Windows 95, until the >manufacturer provided a proper Windows driver for it.
I will note that Windows 95 *could* use DOS drivers. I/O performance suffered horribly since DOS drivers weren't thread safe, but there was a copy of DOS in the system VM for this purpose, even if it had nothing to do under normal circumstances. But to some degree this is a philosophical debate that will be present whenever you have a transition from a CPU architecture without protected memory to one with it and you move incrementally from a single-tasking OS to an environment where multiple instances of that single-tasking OS are virtualized alongside each other. At what point does your protected memory management software cease being an application running in top of the legacy OS and start being the actual OS? Is it the first software package that runs the legacy OS entirely in the architecture's equivalent to v86 mode, even if it remains single-tasking and falls back on the legacy OS for all hardware services except memory management? Is it the first software package that allows multi-tasking multiple instances of the legacy OS? Is it the first software package that prevents applications from accessing system memory? Is it the first software package that provides its own driver layer that bypasses the legacy OS? Is it the first software package that completely removes the ability for the legacy OS to access hardware at all? The two bit things I will point out / opine here are: 1) The software that has control of the machine is different (EMM386 vs VMM32) depending whether you load Windows or not on a Win95 system. 2) Whether you say it is running "on top" of DOS or not VMM32 is the product of an incremental evolution of the DOS ecosystem, not an OS built from the ground up like NT, so it to some degree makes sense to say that Win95 *is* DOS. _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
